California will become the sixth state - and by far the most populous - to legalise and tax sales of recreational cannabis, completing a shift along the US west coast, with Massachusetts and Maine on track to change their laws on pot in 2018.

James Reed smokes a joint during the Denver 420 Rally at Civic Center Park in Denver, Colorado on April 20, 2017. The rally, held annually, is a celebration of both the legalisation of cannabis and cannabis cultureCredit:
AFP

With California's nearly 40 million residents joining the fold, more than one in five Americans will now live in states where people can legally smoke a joint or enjoy...